[AL] Problem with Allegro/X11

[Stephan B. <sb...@op...>]

Hello!

I have a problem with the X11 driver of Allegro. If I do the following, the mouse pointer
is not updated (removed) correctly:

for(;;)
{
	acquire_screen();
	show_mouse(NULL);
	draw something on the screen
	show_mouse(screen);
	release_screen();
	wait for some time
}

I tested on two different linux machine with two different X11 servers/set of libraries.
It does not fail under Windows and Linux/vgalib. To be (more or less) sure that the problem 
is caused by Allegro, I extended example program exmouse.c in the Allegro source tree as follows:

diff exmouse.c.orig exmouse.c
126a127,152
> #if 1
>       {
>               int i,j;
> 
>               i=0;
>               for(;;)
>               {
>                       acquire_screen();
>                       show_mouse(NULL);
>                       rectfill(screen,10,10,150,50,i);
>                       show_mouse(screen);
>                       release_screen();
>                       i++;
>                       if(i==256)
>                               i=0;
>                       for(j=0;j<10;j++)
>                       {
> /*#define AVOID_PROBLEM*/
> #ifdef AVOID_PROBLEM
>                               show_mouse(screen);
> #endif
>                               yield_timeslice();
>                       }
>               }
>       }
> #else
127a154
> #endif

Increasing the number of times "yield_timeslice()" is called increases the problem/let's 
the problem show up, enabling "show_mouse(screen)" by setting "AVOID_PROBLEM" solves it. 
Is this a already known issue?

Stephan